Multichannel time recording of a plurality of events



F. VlLBlG Oct. 25, 1955 MULTICHANNEL TIME RECORDING OF A PLURALITY OFEVENTS 2 Sheets-Sheet 1 Filed May 5, 1953 7 afdlw: ZZZZiS 9. k i L EG EINVENTOR.

Oct. 25, 1955 F. VILBIG 2,721,782

MULTICHANNEL TIME RECORDING OF A PLURALITY OF EVENTS Filed May 5, 1955 2Sheets-Sheet 2 r 14 W K -IIIII I I zgm f i unm //////4' I Z UnitedStates Patent MULTICHANNEL TIME RECORDING OF A PLURALITY OF EVENTSFriedrich Vilbig, Cambridge, Mass. Application May 5, 1953, Serial No.353,246

1 Claim. (Cl. 346107) (Granted under Title 35, U. S. Code (1952), sec.266) The invention described herein may be manufactured and used by orfor the Government for governmental purposes without payment to me ofany royalty thereon.

This invention relates to a multichannel light control recording devicefor recording the time duration and correlation of a plurality ofdifferent measurement events.

This invention contemplates the recordation on film, or other recordreceiving memory device, of a plurality of events that may be happeningsimultaneously, alternately, successively, sequentially, oroverlappingly, whether such events are happening periodically orrandomly. This is accomplished by having a plurality of light passagesclosed by light shutters which passages terminate at the light outletends thereof on a ground glass plate. A light source is positioned atthe inlet ends of the light passages whereupon the opening of any of thelight passages by the light shutters will allow the light in thosepassages to fall on the ground glass plate at separate points at theends of those open light passages. The images of those lighted points onthe ground glass are brought to focus on a focal plane through anobjective lens and, in the illustration of the invention herein, a filmis slowly moved along the focal plane whereby the light points from thevarious light passages are exposed on the slowly moving film, it beingunderstood that the entire structure hereinabove is sealed againstexterior light. Each light shutter is operated by electrostatic orelectromagnetic means in which the electric current therefor is switchedby the event to be recorded for the time duration that the eventcontinues, for example, the time that a door is open or that a key isdepressed, etc. Each light passage image on the ground glass will focusat a different point on the film through the object lens so that if thefilm be made to travel normal to the plane of all the light passages,each light passage image would be able to expose and produce a separateline on the film and thus a comparison of the happening of all theevents can be made.

Where it is desirable to put reference lines on the film, or othermemory recording device, separate continuously open light passages maybe used in combination with the shuttered light passages. Thisarrangement is quite useful where the invention is adapted for recordingmusical notes and the events come from a musical writer.

in order to produce the light points on the ground glass plate in closerelation such that, if all the light passages were open, a continuouslight pattern or light band would be formed, the light passages arearranged in two angular series crossing each other such that the exitsof all the light passages are adjacent or juxtaposed. In this manner agreat number of light passages can concentrate their exit patterns in asubstantially continuous light band whereby a great many events, forexample a hundred or more, can be recorded with a relatively small pieceof equipment. It is therefore a general object of this invention toprovide a device for recording on film, or other memory recordationimplement, the time duration and time correlation of a plurality ofevents which may happen together or separately, periodically orrandomly.

These and other objects, advantages, features, and uses will become moreapparent as the description proceeds when taken in view of theaccompanying drawings, in which;

Fig. 1 is an isometric view of the invention with parts and portionssectioned to disclose constructional details;

Fig. 2 is a portion of the front face of the ground glass plate withexamples of light passage patterns thereon;

Fig. 3 is a sectional view of the preferred form of the light shutterused;

Fig. 4 is a partial end sectional view of a modified form of lightshutter;

Fig. 5 is a partial side sectional view of the modified light shuttershown in Fig. 4; and

Fig. 6 is a portion of the film, or memory recording device, showing therecorded events.

Referring more particularly to Fig. 1, the multichannel recording deviceis inclosed in a light impervious case 10 having a base 11. Mounted onthe base 11 within the case are a light source 12, a light channelingunit 13, and a film or other memory recording unit 14.

The light channeling unit 13 consists of a block illustrated in threesections 15, 16, and 17 although this unit may be made in more or lesssections where desirable and feasible. The lower section 15 provides abase and is substantially plain. On section 15 is mounted the secondsection 16 having a plurality of light channels therein in two parallelangular series 18 and 19, each parallel series crossing the otherparallel series. The two series of light channels 18 and 19 are cutcompletely across the top surface of the section 16, each channel beingsubstantially square in cross-sectional area, whereby light from thelight source 12 may pass through the light channels. The exit ends ofthe light channels are adjacent such that light emitted will bealternate from one series of passages to the other. The underside of thesection 16 has channels 2% and 21 of which 20 are of greatercrosssectional area than the channels 21 in order to trace a bolder lineon the film or memory device, as will later be better understood. Thecrosssectional size and spacing of the light channels 20 and 21 can bemade for particular purposes in drawing reference lines on the recordingtape or film, or may be omitted altogether, but are herein illustratedas having every fourth channel 20 and three intermediate channels 21spaced such that they appear under every fifth light channel 18 or 19,as will later appear feasible. The light channels 20 and 21 are outcompletely across the undersurface of the section 16 and perpendicularto the light exit face to provide open light passages from the lightsource 12 to the exit face with sections 15 and 16 together as shown.

The top section 17 is positioned over the section 16 wherein the lightchannels 13 and 19 become light passages. In the under surface of thesection 17 are elongated pockets 25 and 26 in two series, the series 25being near the light exit face and the series 26 being near the backface. The pockets 25 and 26 house electrostatic shutters, soon to bedescribed, which normally close the light passages 18 and 19. While thelight shutters and pockets are constructed exactly alike, for thepurpose of explanation herein the light shutters in pocket series 25control the light passage series 18 and the light shutters in pocketseries 26 control the light passages 1?. The positioning of the lightshutters in series as explained above is not necessary except insofar asrequired by space limitations.

On the light exit face of the composite sections 15, 16, and 17 is aground glass plate 30 which is of a size to completely cover all thelight passage exits. The light source 12 is preferably a tube type knownas the Sotfitt lamp which is an elongated cylindrical frosted tubehaving a tungsten filament extending lengthwise thereof. Light along thetube 12 is sealed out of all the case except through the light passages.Light from the source 12 will pass through all open light passages toform light patterns on the ground glass plate 30 as shown in Fig. 2 ofwhich 31 are examples of light coming through light passages 20, 32 areexamples of light coming through light passages 21, and 33 are examplesof light coming through light passages 18 and 19 where the respectivelight shutters are open.

The film recording unit 14, illustrated herein for explanation althoughother light sensitive memory recording devices may be used, is housed ina separate compartment 40 of the case divided off by a wall 41. The wall44 has a single opening 42 in which is mounted an objective lens 43.Brackets 44 support two film reels or rollers 45 and 46 which willsupport a film 47 thereon in the focal plane of the lens 43. Theunexposed film is on reel 45 and reeled onto the roller 46, the reel 46being driven slowly by a motor 48 through a gear reduction means 49. Byway of illustration the exposed portion of the film 47 shows the boldand secondary reference lines formed by the open light passages and 21,respectively, and the exposed patterns resulting from corresponding openlight passages 18 and 19. Reference characters show the correspondinglight patterns on the glass plate of Fig. 2 which illustrates the filmexposure resulting from the camera effect of imaging the light patternsof the ground glass plate 30 on the film 47.

Referring now more particularly to Fig. 3 where a longitudinalcross-section of one of the electrostatic light shutters is shown, thepocket referred to above in the section 17 is identified as 25 in thisview and is representative of the pocket portion 26 as well. In thispocket is a semiconducting slate slab 51 having an upwardly curved lowerface 52 toward the light exit face 4 on which the ground glass plate ismounted. On the upper and lower surfaces of the slate slab 51 are metalplates 53 and 54 which are connected in circuit through an electricswitch 55 to a voltage source of some 200 to 300 volts. Attached on theunderside of section 17 in back of the pocket 25 is a metallic shutterstrip 56 as of Phosphor bronze having 21 depending lip 57 on the forwardend thereof that normally rests across a light passage 18 or 19. As maybe seen in the view of Fig. 1, the depending lip 57 rests in a planeangularly of the plane perpendicularly through the longitudinalcenterline of the strip in order to be positioned in a planeperpendicular to the side walls of the light passage. Upon the closingof the switch 55 the shutter strip 56 will be lifted from the dottedline position to the position shown opening the light passage. Openingof the switch 55 will immediately return the shutter to the dotted lineposition by its inherent resiliency. This electrostatic means is knownas the Johnson-Rahbek effect and is accomplished in the followingmanner. The upper and lower surfaces of the slate slab 51 are ofmicroscopic roughness in the order of 1O to l0 centimeters. The metalplates 53 and 54 contact the slate slab 51 only at specific points. Atother points practically the full potential exists between the metalplate and the slate surface which forms a kind of a condenser in whichthe slate surface and the metal plate are the two condenser plates andhave a distance d=10- to l0" centimeters. Because of the high potentialand the small distance a large force is produced,

where A is the area and E is the voltage. The force depends on thesquares of the slope 52 for lifting the shutter 5657 but for the sloperepresented the force is sufficient to provide a fast acting shutter.While the voltage source for the light shutters is illustrated in Fig. 3as a battery, it is to be understood that an alternating voltage may beused with frequencies up to 5 or 6 megacycles.

It may be readily understood from the above description that a pluralityof different events can all be recorded on the film 47 by arranging theswitch of each electrostatic light shutter to be actuated by the eventto be recorded, as for example, movements of measuring probes,multi-channel telegraphy, radio telemetering, musical notes, etc. Withthe individual switches 55 so arranged and the motor 48 operating tomove the film at a fixed speed, the events will be recorded asillustrated on the film 47, Fig. 1, and in Fig. 6. As a practicalexample of one of the many uses of the invention the switches 55 mayeach be positioned to be actuated by individual keys of a piano or asimilar musical keyboard with the key and switch corresponding to theproper note to be produced on the film. For a simple construction theordinary note types cannot be used where time will be given by differentshapes of the single note heads. Instead the length of these differentnotes wil produce corresponding lengths of lines but it is not possibleto write half notes by using the standard signs of the sharp and flat.This is avoided by indicating the notes not only on the lines and in thespaces but also indicating half tones on the bottom third and on the topthird of the spaces as shown by 60 in Fig. 6. By playing the piano orthe musical keyboard the notes are written on the film 47. The musicalbars 61 may be produced on the film by actuating a master switch in anywell known manner (not shown) to place all the light shutters in circuitsimultaneously for an instant, or by closing a condenser circuit which,upon discharge, will produce an instantaneous voltage in all the lightshutter circuits. Indications of volume (p, pp, my, 1, and fj) can beproduced by special keys which give light signals that can be recordedon the film.

As shown in Figs. 4 and 5 the operation of the light shutters may becarried out in other ways. In the modification shown herein the shutterstrip may be attracted to open position by an electromagnet 70 in whicha pole end 71 may extend into an opening 72 in the section 17 just abovethe shutter depending portion 57 of the light shutter strip 56. Theclearance between the pole end 71 and the shutter strip 56 need be onlysufiicient in the deenergized condition to permit sufficient lift of theshutter to clear the light passage in the energized condition of theelectromagnet. The openings 72 are made sufficiently larger than thelight passage to provide a shoulder therein on which a brass or plasticdisc 73 is placed to prevent sticking of the strip 56 to the pole end 71as a result of residual magnetism. Each electromagnet 70 is individuallyconnected through a switch 55 to a voltage source as in the modificationof the electrostatic shutters except that low voltage may be used. Theoperation of the multi-channel recording device using electromagneticoperated light shutters is the same as the operation of the device usingthe electrostatically operated light shutters.

There may be uses of this invention where it would be desirable to haveactual time printed on the film, or other recording implement, forreference purposes. A time clock unit could be installed in thecompartment 40 in any well known manner as shown in the patent to F. E.Garbutt issued on January 6, 1931, and bearing the Patent No. 1,787,940,to print the time at intervals along the film 47.

It is to be understood that many modifications, changes, relation ofparts, and proportions of the elements may be made in the illustratedforms of the invention to adapt it for various uses, whether mentionedherein or not, without departing from the spirit and scope of theinvention and I desire to be limited only by the scope of the appendedclaim.

I claim:

A multichannel recording device for recording the time duration of aplurality of data comprising a housing, a first chamber at one end ofsaid housing containing a light source extending thereacross, a secondchamber positioned at the opposite end of said housing and havingmounted therein a film recorder, a ground glass image receiving screenand a condensing lens for forming an image of the light pattern on thescreen in the plane of the recording film, and means for transmittinglight from said first chamber to said second chamber to form illuminatedareas on said ground glass screen representative of respective events tobe recorded comprising a first set of parallel light transmittingchannels extending from said first to said second chamber and inclinedin a horizontal plane in one direction with respect to the longitudinalaxis of said housing, a second set of parallel light transmittingchannels extending between said first and said second chambers in acommon plane with said first set of channels and inclined in theopposite sense from the longitudinal axis of the housing to intersectsaid first set of channels, intersecting pairs of light transmittingchannels having common light inlets in the first chamber and commonlight outlets in the recording chamber and adapted to form juxtaposedlight spots on the ground glass screen when both channels of a pair ofchannels intersecting at the outlet are opened for light transmission, ashutter in each recording channel and adapted to be open for theduration of the event to be recorded in the corresponding channel, andelectrical means for selectively operating the shutters.

References Cited in the file of this patent UNITED STATES PATENTS2,180,417 Huebner Nov. 21, 1939 2,220,474 Bryce Nov. 5, 1940 2,322,602Terry June 22, 1943 2,392,224 Bryce Jan. 1, 1946

